A NEW PROTECTIVE AGENT AGAINST X-RAY DAMAGE OF HEMATOPOIETIC STEM CELLS

Aim of radiotherapy is the cancer cell damage destroying their ability to divide and grow, by using high-energy ionizing radiation (IR), although causing side effects on healthy cells. A limiting factor in the use of radiotherapy is the acute and long-term bone marrow injury: IR induces hematopoietic stem cell apoptosis and senescence. The direct ionization of cellular macromolecules generates the formation of reactive oxygen species (ROS), which lead to functional cell alterations1. A new isoform of human MnSOD, isolated from liposarcoma cells and obtained in a synthetic recombinant form (rMnSOD), exerts the radiosensitizing effect for tumor cells and meanwhile a radioprotective effect on healthy cells2. In our study, we analyzed the rMnSOD radioprotective effect on human umbilical cord hematopoietic stem cell (CB-HSCs). Mononuclear cells were isolated from cord blood after informed consent of healthy donors, received by the Cord Blood Bank (Ba.S.C.O) of “Santobono Pausilipon” hospital in Naples, by using Ficoll/Hypaque gradient. Cultured CB-HSCs were incubated with 0.5 μM MnSOD for 24h and then irradiated (2Gy) by using Mevatron (Siemens, Italia). After irradiation, an aliquot of cells was immediately stained with 0.4% Trypan Blue and cell viability and senescence was evaluated after 24h from irradiation, by using Guava Easy Cyte Flow Cytometer. Our preliminary results showed a viability increase of rMnSOD treated cells after IR exposure, compared to the only irradiated cells. Senescence evaluation confirmed the protective action of rMnSOD. HSC protection from IR should be a primary goal in the development of new medical countermeasures against radiation damages. Refernces 1. Shao L, et al. Antioxid Redox Signal 2014;20(9):1447-6 2. Borrelli A, et al. Free Radic Biol Med 2009;46(1):110-6